The purpose of this research is to characterize the relationship of reduced glutathione (and associated enzymes) to secretion, particularly its possible importance to the function of the Golgi apparatus, its role in disulfide bond formation of secretory proteins and its function in cell recovering (including membrane recycling). The two models being employed to investigate glutathione in secretory processes are the isoproterenol-stimulated acinar cells of the rat parotid gland and cartilage and bone cells of demineralized matrix-induced endochondral bone. Enzyme assays of glutathione peroxidase, which utilizes reduced glutathione as a substrate, and glutathione reductase, which generates reduced glutathione from the oxidized form are being performed. Preliminary data suggest that in isoproterenol stimulated parotid glands there is a peak of glutathione peroxidase activity 4 hours post-injection and glutathione reductase levels rise significantly between 1 and 4 hours post injection. In the bone-induction system, glutathione peroxidase peaks on day 3 after implantation of demineralized bone matrix and then remains elevated during cartilage and bone development. Glutathione reductase also peaks on day 3 but falls during both cartilage and bone formation.